One idea could be that the Master Chief somehow gets transported to Skyrim. He could use his advanced combat skills and high - tech weaponry in the medieval - like setting of Skyrim. For example, facing off against dragons with his energy sword, creating a really cool contrast between the high - tech and the fantasy elements.
Maybe the Covenant discovers the world of Skyrim. They see the magic there as a new form of power to conquer. The Dovahkiin, on the other hand, could see the Covenant as a new threat to Skyrim. This would lead to epic battles between the two different forces, with the Dovahkiin using shouts and the Covenant using their plasma weapons.
Another plot could involve the Forerunners having some sort of connection to the ancient races in Skyrim. Perhaps the Dwemer were influenced by Forerunner technology in the past. A group of researchers from Halo's universe could come to Skyrim to study this connection, and they team up with the Dovahkiin to uncover secrets that could change both universes.
A cool plot could be that the Sage of Six Paths in Naruto's world had a connection to Skyrim long ago. When Naruto unlocks some hidden power within himself, it accidentally triggers a link to Skyrim. Once in Skyrim, he discovers that his chakra is linked to the dragon shouts. He has to go on a quest to learn more about this connection. He meets the mages in the College of Winterhold, who are fascinated by his chakra abilities. Together, they try to figure out a way to use Naruto's power to stop a great evil that is threatening both Skyrim and, through the link, Naruto's own world.
One idea could be that the Master Chief is somehow transported to Skyrim. He might use his advanced combat skills and technology to deal with the dragons. For example, his energy shields could protect him from dragon fire. Another plot could involve the races in Skyrim getting access to Halo's weaponry and having to figure out how to use it. Maybe the Dwemer could reverse - engineer Covenant weapons.
One possible plot could be that Percy and his demigod friends are somehow transported to the Halo universe. They could team up with the Spartans to fight a common enemy, like a new kind of powerful monster that has emerged in the Halo world due to some strange rift between the two universes. Percy could use his water powers in unique ways, for example, to short - circuit some of the Covenant technology which might be vulnerable to water in this crossover scenario.
The Master Chief is an obvious choice. His stoic and powerful presence would be really interesting in the Skyrim setting. He could be like an otherworldly hero, and his Spartan abilities would make him a force to be reckoned with against Skyrim's foes.
One possible plot could be Naruto getting transported to Skyrim. He might be mistaken for a strange new race at first. As he explores Skyrim, he could use his ninja skills to fight the dragons. Maybe he teams up with the local warriors and teaches them some of his jutsu in return for learning about Skyrim's magic. His ability to move quickly and stealthily would give him an edge in the dangerous world of Skyrim.
One idea could be that the Master Chief from Halo is transported to the Destiny universe and has to team up with a Guardian to stop a new threat that is using technology from both universes. For example, the Covenant and the Fallen might be working together under a powerful new leader.
One idea could be that Master Chief gets transported to the Marvel universe. He teams up with the Avengers to fight a common enemy like Thanos who has somehow obtained Covenant technology. His Spartan abilities would be a great addition to the team.
One plot idea could be Master Chief getting transported to the Marvel Universe. He could team up with the Avengers to fight a common threat like Thanos. His advanced combat skills and Spartan armor would add a new dynamic to the team. Maybe he'd be initially distrusted, but prove his worth in battle.
Well, perhaps in the fanfiction, Lara Croft is exploring an uncharted planet when she stumbles upon a Halo ring. This attracts the attention of the Covenant, and Master Chief arrives to deal with the situation. At first, there's some tension between them as they come from different worlds and ways of doing things. But as they start to understand each other's motives and skills, they combine Lara's knowledge of ancient mysteries and Master Chief's combat expertise to fight the Covenant and figure out the secrets of the Halo ring.
One possible plot twist is that the dragons in Skyrim are the ancestors of the dragons in Game of Thrones. What if there was a secret connection that allowed a character to travel between the two worlds through the dragons? For example, Daenerys discovers that her dragons have a hidden ability to open portals to Skyrim. This would not only be a huge shock but also open up a world of new adventures and interactions between the characters of both universes.